Critical Reasoning

An antique and curiosity shop is weighing the advantages of renewing its regular advertisements in a monthly trade publication. The shop originally placed the ad in order to increase business, but found that majority of its sales are made to those who do not read the publication and have not seen the ad. The shop is considering canceling the advertisement in that publication in order to save money.

Answer to which of following would be LEAST relevant to shops decision?
a.how does the cost of the ad compare to the profit from the purchases made by those who have responded to it
b.are the other trade publications that attract the shop’s typical clients in which an ad would be likely to reach customers at same cost
c.is a significant proportion of the shop’s competitors satisfied with the effect of their advertisements in trade publications
d.how many buyers who responded to the ad were professional antique dealers who generally make relative expensive purchases
e.in any significant change expected in the patter of the trade publication circulation

OA after some discussion .

[spoiler]Could narrow it down to C & E and then got a bit lost . Why is E wrong ?[/spoiler]